Traveler core rules deck plans, first impressions

[bytedruid]

The inability of grav plates to fail catastrophically seems to be a pretty standard space opera trope. There are very few sci fi ships that are not built in this manner. Either the setting is rockets and tailsitters or the ships are built as if grav doesn't fail under acceleration.

Actually I wouldn't say it's all that rare. It was a central plot point of Star Trek 6 the Undiscovered Country anyway. Typically engineers design standard consumer items in a fail safe manner. For example if you take your hand off the yoke of a Cessna 172 it returns itself to level flight, etc. In this case the fail safe is to allow for acceleration, potentially away from something dangerous, even when the plating doesn't work.

Given this consideration, and the fact that form follows function, I'd presume the form of most non-atmospheric ships would be more like an office building then a steamship. For atmospheric craft, ease of access while planet-side could dictate other forms.

So to flip the question on it's head, why would you even want to put the primary acceleration vector parallel to the floor? What first-principles benefit is there to be gained from that?

 

[Vormaerin]

Your ship isn't an cone with tiny floors and lots of ladders you have to climb up and down? You want your ships to be like the Millenium Falcon, the Serenity, or most other major space opera ships that are not tailsitters?

If you want me to speculate on how reactionless space magic drives from 3500 years in the future work from an OSHA perspective... gonna plead "not qualified to answer". Though I generally go with the "magic space drives are intrinsically inertial dampening" like mentioned above if any of my players actually ask. Frankly, if you have a high thrust ship, even a tailsitter would be fatal if the inertial dampening failed. Granted most civilian ships are not able to accelerate at high G.

Actually, I'm not sure if you even have to point the bow of your ship in the direction you want to travel with maneuver drives. That may just be aesthetics. Obviously, with reaction drives you do.

Ship design is 'what do you think is cool'. If you want tailsitters, reaction drives, and ships like that, then there is a set of Traveller rules for that (2300/Aerospace Engineer's Handbook). Next year's Pioneer rules are likely to lean into that even more. If you like "standard" space opera ships, you use the Core/High Guard rules. Want hyperfast even crazier tech ships? Go with the Mindjammer version of Traveller ship design.

The vast majority of deckplans are for space opera ships because that's what's most popular and what the artists like designing. But you can find tailsitters, mostly in the 2300 line. That gets you ships like this:

 

[Geir]

Azhanti High Lightning was a tail-sitter design, one of the reasons I really liked that ship. Could only do 2 gees, so it didn't matter much if gravitics failed. The most important deal with a tail-sitter is that the decks both match the direction of thrust and the direction of gravity if you power it down on the surface of a world. Ironically, you can't do that with the AHL, but it's too big to land in any case. The Mercenary cruiser fits the bill, though. Spheres are the most surface area efficient ships, so there ought to be more of them...

 

[bytedruid]

The vast majority of deckplans are for space opera ships because that's what's most popular and what the artists like designing.

Essentially that's what I figured. And after all, it's a game, so whatever is fun for most people and pays the authors is right by definition.

Thanks to everyone who responded, especially those like AnotherDilbert who explained M-Drives and provided examples of other books and plans.

I've picked up most of the 2300 AD line already, but this was my first time actually reading the core rules. Basically I approached the game backwards, and was struct by just how unreasonable most of the core ship line appears on first glance to anyone with a STEM background. Given what I've read here, I see this as an opportunity to financially support artists who've taken the time to create more physically realistic deck plans. There's a diverse secondary market out there, and most of those creators could probably use a few more sales.

Best,

 

[Condottiere]

1. I was always impressed with the skyscraper configuration of the Azhantis, since it made logical sense to have elevators for mobility.

2. Presumably, you can shut off the inertial compensation (field), and just have the spacecraft under constant one geeish acceleration.

3. Non gravitated hulls have a half off discount.

4. The problem with constant acceleration is increased velocity, so perhaps have floors and ceilings that can double as each other.

 

[Vormaerin]

Essentially that's what I figured. And after all, it's a game, so whatever is fun for most people and pays the authors is right by definition.

Thanks to everyone who responded, especially those like AnotherDilbert who explained M-Drives and provided examples of other books and plans.

I've picked up most of the 2300 AD line already, but this was my first time actually reading the core rules. Basically I approached the game backwards, and was struct by just how unreasonable most of the core ship line appears on first glance to anyone with a STEM background. Given what I've read here, I see this as an opportunity to financially support artists who've taken the time to create more physically realistic deck plans. There's a diverse secondary market out there, and most of those creators could probably use a few more sales.

Best,

Traveller is a game that can be played a lot of different ways. You can use it to run games similar to Star Wars, Star Trek, Stargate, Firefly, Alien, or the Expanse quite easily. It's just a matter of which set of tech assumptions you want to use. The most popular Traveller setting is Charted Space, which uses 60s/70s space opera for some of its core design conceits, but you aren't constrained by that. Any more than you have to play in the Forgotten Realms if you play D&D.

Space ship design is one such tech conceit. Psionics are another. Handheld laser weapons are yet another. Any or all of these things could be "unreasonable" depending on what you are going for in your game. Nobody actually knows what our tech capabilities will be like in 200 years, much less 3500 years with even higher tech aliens to get secrets from.

Supporting artists who make the kind of content you like is definitely an A+ plan, regardless.

 

[Sigtrygg]

Reaction drive - HEPlaR, fusion rocket, ion drive etc
These would produce the illusion of gravity thanks to Newton's third law.

A reactionless drive is reaction less - no reaction forces. So no simulated gravity due to thrust because the third law does not apply.

I agree with Geir, if the drive is reactionless (Mongoose gravitic or MegaTraveller technobabble-hand windmilling) then there is no gravitational effect due to "pseudo-thrust".

 

[AnotherDilbert]

A reactionless drive is reaction less - no reaction forces. So no simulated gravity due to thrust because the third law does not apply.

You can of course play your game as you see fit, but you are conflating reaction-less with field effect: they are not the same.

E.g. gravity is a field effect (affects the entire ship and anything in it equally), but is not reactionless, it obeys Newton's laws.

By Traveller canon (MT RM p56) m-drives are reactionless (does not expel propellant) but the thrust is applied only to the drive, the drive then propagates that thrust to the rest of the ship (and any occupants) by contact in accordance with Newton.

 

[Sigtrygg]

Hence they are a reaction drive - thrust and reaction to thrust - so not a true reactionless drive.

See the equivalence principle, gravity is not a force therefore there is no reaction to it.

 

[AnotherDilbert]

Hence they are a reaction drive - thrust and reaction to thrust - so not a true reactionless drive.

There is no external reaction to the entire ship accelerating, but Newton works normally within the ship. The m-drive pushes the hull, that pushes the occupants in accordance with Newton's laws.

See the equivalence principle, gravity is not a force therefore there is no reaction to it.

Sorry, I have no idea what you mean. Gravity is a force field, or by F=ma an acceleration. It affects both involved objects equally but in opposite directions. Just like Newton says.

We can of course (with Einstein) say that gravity is a perceived acceleration, or by F=ma a force.

 

[Vormaerin]

Arguing that there is a canon definition of how maneuver drives work is dubious. Megatraveller says its magic forces pushing against the thrust plates. T5 says its pushing against the gravity of planets and stars. I don't think it says one way or the other in Mongoose traveller, just that it is a reactionless drive that applies acceleration to the ship.

Does anywhere actually say that the space magic can only push on the aft hull of the ship? Can ships slow down without flipping over?

 

[Sigtrygg]

What you are describing is akin to someone running into a wall to move a box - it doesn't work.
As to the nature of gravity -

 

[AnotherDilbert]

Arguing that there is a canon definition of how maneuver drives work is dubious. Megatraveller says its magic forces pushing against the thrust plates. T5 says its pushing against the gravity of planets and stars.

Yes, but they are not directly contradicting.

I don't think it says one way or the other in Mongoose traveller, just that it is a reactionless drive that applies acceleration to the ship.

Agreed, Mongoose avoids explanations.

I'm assuming the different editions are different incomplete views of the same reality, so generally all valid at the same time. YMMV.

Does anywhere actually say that the space magic can only push on the aft hull of the ship?

MT SSOM has some discussion: The M-drive can be anywhere, but for somewhat silly practical reasons it's generally in the aft.

Can ships slow down without flipping over?

Again MT SSOM say we can, but inefficiently:

Full thrust is only aft, and only 10% reverse thrust.

MgT says you (generally?) flip over:

MgT Referee's Companion, p149:
Most space vessels have a main drive which applies thrust in one direction, and smaller manoeuvring units to point the ship. Changing direction is a matter of realigning the ship and then using the main drive to thrust in the chosen direction. However, the ship retains momentum in whatever direction it was going and must cancel this or include it in the new course calculations.

 

[Condottiere]

I think you do have to be careful with the placement of the manoeuvre drive.

Lateral or reverse thrust that penetrates through sensitive equipment, or the crew, is likely to have adverse effects.

 

[phavoc]

Usage of space using a 'flat' design with the engines at the back is more efficient than a tail-sitter design. If you are a cargo ship, your choices are to have a central shaft to load each deck from, or else a cargo hatch at each deck.

It's been a long-running question in regards to exactly WHAT on the ship generates the inertia dampener field. Grav plates are mentioned, as well as mentioning that you can adjust them, which leads you to believe that grav plates can be created on a smaller scale scale (perhaps by square meter?). From a pure safety point I'd expect that each grav plate section/room would have built-in capacitors that would make an instantaneous failure impossible. Of course since we don't know the effect range of the field, one would have to ask how far the field is from the floor (which affects ladders/crawlspaces, and whether or not the field would project outside of the hull - lots of questions on the tech that haven't ever really been answered as far as I can recall. As far as the idea of corridors becoming death traps, I would tend to think that designers of starships would take that into consideration, let alone safety authorities, and there would be something to prevent, or at least minimize this risk.

We also don't know, from the drive perspective, how they really work as far as physics go. The MGT SOG was a great attempt at explaining some of these things to gear heads, though the drive explanation fell rather flat in my opinion because they postulated the regular use of 400% power to land and take off a starship. While not impossible, it's relatively impractical. With the advent of anti-gravity technology it makes far more sense (and is much more practical) to have ships land/take off while horizontal. Aviation designers would use such things in a heartbeat today if the tech was available. The arguments FOR it's use exceed those to NOT use it.

 

[Vormaerin]

Essentially, they are twisting themselves into knots trying to maintain reaction drive behavior without requiring the fuel to power it or granting the ability to use the reaction tail as a weapon.

If there's big drama about inertial dampening failing, why not put the drive plates on the "floor" of the ship instead of the back wall? Or embrace that your reactionless drive means that ship facing isn't a relevant factor, just existing vectors? It all seems needlessly complex, especially since the game doesn't even use facing in in the generally abstract ship combat system.

 

[bytedruid]

Usage of space using a 'flat' design with the engines at the back is more efficient than a tail-sitter design. If you are a cargo ship, your choices are to have a central shaft to load each deck from, or else a cargo hatch at each deck.

I'd buy that. Though, in a setting based on anti-gravity, why not just float the cargo up to where you need it? If horizontal is better in practice, then it means that at least sometimes it's convenient not to require gravity manipulation to get a job done.

Nonetheless, assuming horizontal layouts are better, then why not design commercial ships as flying saucers? It's the most space efficent flat shape. Have the M-drive integrated into the floor (kind of like the battery pack on a modern electric vehicle) and float up out of the atmosphere and fly flat-side-first when in space. Dedicated aircraft would still have a small (probably 1/5 g) M-drive in the back for atmospheric travel, but the primary drive would always be in the floor.

Warships on the other hand would have many decks because it's helpful to present a small frontal aspect in battle. With such designs, warships would be immediately distinct from merchant craft. Just as tanks are immediately distinct from vans in our world.

The only reason I see for making almost all Traveller craft look like their terrestrial analogs (ships, planes, etc), is player familiarity. As mentioned upstream, it's probably why the '70's shows did it. The reason I like to let first principles dictate design is you get stuff that feels really different, because the environment and the postulated tech are different. Which to me is cool, and helps promote suspension of disbelief.

 

[bytedruid]

1. I was always impressed with the skyscraper configuration of the Azhantis, since it made logical sense to have elevators for mobility.

Which book is this design in? I might purchase it. Also, I'm not familiar with all the abbreviations yet so if you don't mind spelling it out that would be mighty handy.

2. Presumably, you can shut off the inertial compensation (field), and just have the spacecraft under constant one geeish acceleration.

I hadn't thought about this aspect, but you're right. If your floor is towards the drive, it does provide an energy saving effect. Fuel efficency has driven many a design.

4. The problem with constant acceleration is increased velocity, so perhaps have floors and ceilings that can double as each other.

I'd presume constant acceleration is a good thing? I mean, it does get you where you're going faster after all.

No need to have ceilings double as floors, just flip the ship backwards for the second half of the trip. When I see ships flying backwards into planetary orbit, burning to shed velocity, I know I'm watching an actual sci-fi show.

 

[AndrewW]

Which book is this design in? I might purchase it. Also, I'm not familiar with all the abbreviations yet so if you don't mind spelling it out that would be mighty handy.

High Guard 2022 page: 258

Or there was the GDW board game: Azhanti High Lightning.

 

[Galadrion]

Which book is this design in? I might purchase it. Also, I'm not familiar with all the abbreviations yet so if you don't mind spelling it out that would be mighty handy.

The Azhanti High Lightning was a warship detailed in one of the original edition (Little Black Book) adventures, way back in the Eighties. I don't think hardcopies are available anymore, but I'm pretty sure you can get PDF copies over at DriveThruRPG.com. Unfortunately, since they are from much earlier editions, they're not directly usable, but if you're interested enough in it, you should be able to carry out your own conversion. Or there may be a fan conversion out there somewhere on teh interwebs.

**And I didn't remember the HG2022 conversion. Sigh. I failed an aging roll...**